The invention relates to determination of a person's sebum secretion level for selection of facial cosmetics of complementary formulation.
It has been observed that the rate at which sebum, i.e. skin oil, is produced and secreted upon the surface of the skin varies from person to person. As a result, facial cosmetics formulated for skin with average sebum production, i.e. so-called "normal" skin, are not suited for use by a person with lower or higher sebum production, i.e. so-called "dry" or "oily" skin. It has beer thought to adjust facial cosmetic formulations to accommodate different levels of sebum production by varying the level of oil and the like, i.e. mineral oil, petrolatum, glycerine, etc., in the formulation to compensate for skin oil secretion, e.g. formulas having lower levels of oil and the like, or oil-free formulas, may be provided in cosmetics labelled for persons with "oily" skin. Cosmetics labelled as being formulated for "dry" skin may include relatively higher levels of oil and the like to help moisturize and protect the skin. The terms "very oily" and "very dry" have also been used.
Others have sought to quantify sebum production. For example, Strauss and Pochi, writing in The Journal of Investigative Dermatology (Vol. 36, 1961), described a procedure for quantitative gravimetric determination of sebum production. Tur et al. U.S. Pat. No. 3,906,933 describes a device for determining skin type, on the basis of sebum content of the skin, and skin surface topography by microscopic examination of an electrostatically charged printing stamp. Miller U.S. Pat. No. 4,532,937 describes a sebum collection device consisting of an open-celled, microporous, hydrophobic polymeric film applied to the surface of the skin with a thin layer of pressure sensitive adhesive. It is suggested that the level of sebum secretion may be determined by examination of translucent patterns in the film, or by solvent extraction. Hofke et al. U.S. Pat. No. 4,623,793 describes a battery-powered device for determining skin type by measurement of the level of monochromatic light passing through a sample.